Back around 1982 I made a rifle for my wife and son (he was 11 at the time) using a 7/8" wide, .50 caliber Green Mountain barrel 34" long and a small Siler percussion lock. It has a pull of 11.5" I think and was a lot of fun for them to shoot. I confess it was a cheap, quick and easy build, schimmel style, as I sensed (rightly) that is would get used "occasionally". I think the gun weighs about 5 pounds. With 40 grains of powder it shoots pretty well and doesn't frighten or punish anyone.